If you need more positive associations for Lettie/Letty, read Neil Gaiman's Ocean at the End of the Lane! There's a fantastic Lettie, she's about 80% of the reason I like the name. It's great as an nn for Violet.

I think Lettie is vintage and sweet. I had it on my list as a nn for both Scarlett and Violet (though we recently dropped Violet). Lottie is less intuitive but, I think, do-able thanks to the central O in Violet. I also think you could get away with Litty/Liddy if you like. But hey, you know me...it takes a lot for me to freak out about nn connections to names.

I'm still torn on the spelling, but I'm liking it more and more! (And honestly, this encouragement of Liddy is not good at all! I'm so going to want to use it now. Is it really not that far-fetched?)

And... another total hair-brained nn idea: How crazy is Violet nn Tilly? It's crazy, isn't it? If Eleanor can get Nell, then theoretically Violet could get Telly/Tilly... And oh, goodness, I definitely should not go there. It's crazy. (I'm crazy!)

@katemcnamelover - och, I know! I definitely would want to use just Violet about 90% of the time, but I really would like to avoid Vi if at all possible! My family has already brought up Vi if I ever use Violet, and I really do not want that. If I ever do get a Violet, I definitely want to be able to tell them, "Her name is Violet. Her nickname is [Tilly, Liddy, Lettie, whatever!]. You may call her Tilly, or Violet, but most definitely not Vi." :] (Who knows if it'll stick, but I can at least try!)

I actually prefer Lottie (I know I am going against the grain) but I think as Violet has an 'o' and all the letters in Lottie it should be fine.

I have your pre-Fast and Furious association to the name Lettie... and it never grew on me. It just isn't my cup of tea. But I will agree with you in the respect that I love Lettie from the Fast and the Furious and she would be a cool name sake.